<!DOCTYPE HTML>
<html>
<head>
<script>
	window.onload = function(){
		var canvas = document.getElementById("myCanvas");
		var context = canvas.getContext("2d");
		
		var radius = 0;
		var angle = 0;
		
		context.lineWidth = 10;
		context.strokeStyle = "#0096ff";
		context.beginPath();
		context.moveTo(canvas.width/2, canvas.height/2);
		
		for (var n = 0; n < 150; n++)
		{
			radius += 0.75;
			angle += (Math.PI * 2) / 50;
			var x = canvas.width  / 2 + radius * Math.cos(angle);
			var y = canvas.height / 2 + radius * Math.sin(angle);
			context.lineTo(x, y);
		}
		context.stroke();
	}
</script>
</head>
<body>
	<canvas id="myCanvas" width="600" height="240" style="border:1px solid black;">
	</canvas>
</body>
</html>